There are various types of one-way clutch assemblies in use today. Such clutch assemblies include sprag-type, roller-type, and pawl ratchet-type assemblies. All of these one-way clutch assemblies work satisfactorily depending upon the particular application in which they are used.
In certain transmissions, increased torque capacity is needed for one-way clutch assemblies. Space constraints also require that the size of the clutch assembly be retained within certain limits. Current one-way clutch assemblies with sprags or rollers are often insufficient to add increased load carrying capacity and still maintain the space constraints.
Pawl one-way clutch assemblies can add increased nominal load capacity for a given package size. The design limits of a ratchet-type pawl clutch assembly are dictated by contact stress between the pawls and the races and/or bending, shear, and hoop stresses generated within the races.
Ratchet clutch assemblies have at least one pawl which acts to lock two notched or pocketed races together in one direction and rotate freely in the other direction. In general, the differences between known ratchet clutch assemblies relate to the control of the movement of the pawls and the effect on that movement by centrifugal forces.
Ratchet clutch assemblies are shown, for example, in U.S. Pat. Nos. 2,226,247, 3,554,340, and 5,449,057. Another ratchet clutch assembly is shown in British Patent No. 2116.
It is an object of the present invention to provide an improved ratchet one-way clutch assembly. It is another object of the present invention to provide an improved ratchet clutch assembly which has improved operation at high speeds.
It is still another object of the present invention to provide a ratchet one-way clutch assembly in which the pawl members are provided with biasing and/or tilting forces toward engagement or disengagement. It is a still further object of the present invention to provide a ratchet one-way clutch assembly which utilizes spring members to place biasing forces on the pawl members toward engagement.
It is a further object of the present invention to provide a ratchet-type one-way clutch assembly embodiment in which spring or biasing members used to bias the pawl members toward engagement also assist in radially and axially restraining the pawl members and keeping them in position.